1. Field of the Invention
This invention relates to a samarium-cobalt type magnet powder which possesses excellent magnetic properties and is suitable for use in making resin magnet.
2. Description of the Prior Art
It is known to make resin magnets from a samarium-cobalt type magnet powder (hereinafter referred to as "magnet powder") which has been mixed with a resin, such as a polyamide resin. Such resin magnets are used in motors, household electrical applicances, etc.
Generally, the magnetic powder is produced by the so-called melt method, which comprises melting and casting metallic samarium (Sm) and metallic cobalt (Co) so as to produce a samarium-cobalt alloy ingot, then heat treating the ingot, and then pulverizing the ingot; alternatively, it is produced by the so-called reduction-diffusion method, which comprises heating a mixture of samarium oxide with cobalt powder, reducing the samarium oxide with a reducing agent such as vaporous or mixed solid calcium, diffusing the formed samarium in the cobalt powder, throwing the formed reaction product into water to form a slurry, and then treating the slurry with water and an aqueous acid solution. Elements such as germanium can be added to the raw material to improve the magnetic properties of the magnet powder.
The magnet powder produced by the conventional method, however, is liable to inconsistency and instability of its magnetic properties. The method itself is complicated operationally. Thus, the magnet powder has not necessarily proved satisfactory.